Power Device

ABSTRACT

Systems, apparatuses, and methods are described for a power device in a power system. The power device may include a plurality of power stages, which may reduce the number of connectors needed for the power system. The plurality of power stages in the same power device may allow the power device to be configured with additional functionalities.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.17/148,996, filed Jan. 14, 2021, which claims priority to U.S.Provisional Application No. 62/961,387, filed Jan. 15, 2020. Thecontents of the aforementioned applications are incorporated byreference herein in their entireties.

BACKGROUND

A photovoltaic (PV) system is a power system designed to supply solarpower by converting sunlight into electricity. PV systems generallyinclude solar panels or “PV modules”. PV modules include a number ofsolar cells. PV systems are used in commercial and residentialapplications. PV systems may include a plurality of power devices (e.g.,direct current [DC] to DC converters). One issue with PV systems is thatthey may include a plurality of physical connections between elements ofthe system, which may require the use of physical connectors that allowan electrical connection (e.g., PV connectors, for example, MC4connectors). The use of these physical connectors may lead to otherissues in the power system (for example, loss of power, arcing, fires,etc.).

SUMMARY

The following summary presents a simplified summary of certain features.The summary is not an extensive overview and is not intended to identifykey or critical elements.

Systems, apparatuses, and methods are described for a power device inpower systems, e.g., PV systems. The power device may include aplurality of power stages thereby reducing the number of connectorsneeded for the power system. Reducing the number of connectors may alsoreduce the loss of power in the system, and may reduce the riskassociated with the connectors. Reducing the number of connectors mayalso increase the ease of installing/setting up and maintaining thepower system. The power device may comprise additional power stages inthe same power device, which may allow the power device to be configuredwith additional functionalities.

In some examples the power device may be configured to control an outputof the power device (e.g., an output current and/or an output voltagegenerated by the plurality of power stages).

In some examples the power device may be configured to perform acurrent-voltage operating point search and/or a peak sweep/peak search(e.g., a peak power search), even at relatively lesser voltages.

In some examples, the power device may be configured to obtain data(e.g., performance data) related to a relatively lesser voltage.

These and other features and advantages are described in greater detailbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

Some features are shown by way of example, and not by limitation, in theaccompanying drawings. In the drawings, like numerals reference similarelements.

FIG. 1A shows a power system, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 1B shows a power system, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 2A shows a power system, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 2B shows a power system, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 3A shows a power device, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 3B shows a power device, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 3C shows a power device, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 3D shows a power device, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 3E shows a power device, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 3F shows a power device, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 3G shows a power device, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 3H shows a power device, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 4A shows a power device, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 4B shows a power device, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 4C shows a power device, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 4D shows a power device, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 4E shows a power device, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 5 shows a power device, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 6A shows a power device, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 6B shows a power device, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 7 shows a power device, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 8 shows a power device, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 9 shows a power device, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 10 shows a power device, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 11 shows a power device, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 12 shows a power device, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 13 shows a power device, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 14 shows a power device, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 15A shows a graph, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 15B shows a graph, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 16 shows a graph, in accordance with certain examples of thepresently disclosed subject matter.

FIG. 17 shows a flow chart of a method, in accordance with certainexamples of the presently disclosed subject matter.

FIG. 18 shows a flow chart of a method, in accordance with certainexamples of the presently disclosed subject matter.

FIG. 19 shows a flow chart of a method, in accordance with certainexamples of the presently disclosed subject matter.

DETAILED DESCRIPTION

The accompanying drawings, which form a part hereof, show examples ofthe disclosure. It is to be understood that the examples shown in thedrawings and/or discussed herein are non-exclusive and that there areother examples of how the disclosure may be practiced.

It is noted that the teachings of the presently disclosed subject matterare not bound by the power systems described with reference to thefigures. Equivalent and/or modified functionality may be consolidated ordivided in another manner and may be implemented in any appropriatecombination. For example, power source 102A and power device 106A, whichare shown as separate units of power system 100 a (FIG. 1A), may havetheir functionalities and/or components combined into a single unit.

It is also noted that the teachings of the presently disclosed subjectmatter are not bound by the flow charts shown in the figures, and theshown operations may occur out of the shown order. For example, someoperations may be executed substantially concurrently or in the reverseorder. It is also noted that whilst the flow charts are described withreference to elements of power systems shown herein, this is by no meansbinding, and the operations may be performed by elements other thanthose described herein.

It is also noted that like references in the various figures refer tolike elements throughout the application. This includes similarreferences, for example, it is to be understood that power source 102Aand power source 102B shown in FIG. 1A may be similar to other powersources 102 described and shown herein, and vice versa. Throughout theapplication certain general references may be used to refer to any ofthe specific related elements. For example, power system 100 may referto any of the various power systems, power device 106 may refer to anyof the various power devices, switches Q may refer to any of the variousswitches, etc.

It is also noted that all numerical values given in the examples of thedescription are provided for purposes of example only and are by nomeans binding.

The terms, “substantially”, “about”, “sufficient”, “efficiently”, and,“threshold”, used herein include variations that are equivalent for anintended purpose or function (e.g., within a permissible variationrange). Certain values or ranges of values are presented herein withnumerical values being preceded by the terms “substantially”, “about”,“sufficient”, and, “threshold”. The terms “substantially”, “about”,“sufficient”, and “threshold”, are used herein to provide literalsupport for the exact number that it precedes, as well as a number thatis near to or approximately the number that the term precedes. Indetermining whether a number is near to or approximately a specificallyrecited number, the near or approximating unrequited number may be anumber, which, in the context in which it is presented, provides thesubstantial equivalent of the specifically recited number.

The term, “controller”, used herein may include a computer and/or otherappropriate processor/processing circuitry and memory. The terms“computer” or “processor” or variations thereof should be expansivelyconstrued to cover any kind of hardware-based electronic device withdata processing capabilities including, by way of non-limiting example adigital processing device (e.g., digital signal processor (DSP),microcontroller, field programmable circuit, application-specificintegrated circuit (ASIC), etc.) or a device which comprises or isoperatively connected to one or more processing devices, or an analogcircuit implementing control logic. The terms “memory” or “data storagedevice” used herein should be expansively construed to cover anyvolatile or non-volatile computer memory suitable to the presentlydisclosed subject matter. The above may include, by way of non-limitingexample, controllers Con, Con1, Con2, 116 disclosed in the presentapplication.

FIG. 1A to FIG. 2B show examples of various power systems 100 with powerdevices 106 according to examples of the present subject matter.

Reference is now made to FIG. 1A, which shows a power system 100 aaccording to examples of the present subject matter. Power system 100 aincludes a plurality of power sources 102A, 104A, 102B, 104B. As anexample, power system 100 a may be a PV power system, and power sources102A, 104A, 102B, 104B may be PV generators (e.g., one or morephotovoltaic cells, strings of substrings of photovoltaic cells, orstrings of photovoltaic panels). Although power sources are describedherein in the context of PV generators, it will be appreciated that theterm power source may include other types of power sources, for example:wind turbines, hydro-turbines, fuel cells, batteries, etc. Power sources104 may be similar to power sources 102.

A first plurality of power sources 102A, 104A may be connected to powerdevice 106A. Power sources 102A, 104A may be in series, parallel, orneither with respect to each other. Power device 106A may include aplurality of terminals configured to connect each individual powersource 102A, 104A to the power device 106A.

A second plurality of power sources 102B, 104B may be connected to powerdevice 106B. Power sources 102B, 104B may be in series, parallel, orneither with respect to each other. Power device 106B may include aplurality of terminals configured to connect each individual powersource 102B, 104B to the power device 106B.

Power device 106A and power device 106B may be connected to one or moresystem power device(s) 110. Power device 106A and power device 106B maybe connected to one another in a series or parallel connection (e.g.,connected to one another at their outputs, with at least one outputterminal of a first power device being connected to at least one otheroutput terminal of a second power device). Power device 106A and powerdevice 106B may be connected to one or more system power device(s) 110.Power device 106A and power device 106B are shown in FIG. 1A as beingconnected in a series connection forming a series string 114 of powerdevices. As an example, an output terminal of power device 106A may beconnected in series to an output terminal of power device 106B. Forexample, power device 106A may be connected to power device 106B using asingle physical connector. Additional power devices similar to or thesame as power devices 106A and 106B may be further connected in seriesas part of series string 114. Series string 114 may be connected tosystem power device(s) 110 via a bus 108 (e.g., a DC bus).

System power device(s) 110 may be, for example, one or more: DC to DCconverter(s) (e.g., buck converters, boost converters, buck/boostconverters, and/or buck+boost converters, etc.), DC to alternatingcurrent (AC) converter(s)/inverter(s), combiner and/or monitoring boxes,etc. System power device(s) 110 may be an inverter for one or morephases (e.g., a one phase inverter, two phase inverter, and/or a threephase inverter, etc.), and may include lines/phases that are not shownherein for the sake of simplicity.

System power device(s) 110 may be connected to one or more loads 112.The one or more loads 112 may include, for example: an electrical grid(e.g., an AC electrical grid), a storage device (e.g., a battery), aresistive device (e.g., a resistor), an AC device (e.g., a motor), etc.

Each power device 106A, 106B may include a plurality of power stages, asdescribed in greater detail below with reference to FIG. 3A to FIG. 6B.The term “power stage” used herein may refer to a converter (e.g., apower converter) or sub-converter that is part of the power device 106.A power stage may be, for example, one or more: DC to DC converter(s)(e.g., buck converters, boost converters, buck/boost converters,buck+boost converters, Cuk converters, etc.), DC to ACconverter(s)/inverter(s), micro-inverter(s), flyback converters, etc.The plurality of power stages may be located inside a single sharedhousing or enclosure of the power device 106 (i.e., inside the samehousing or enclosure as each other). In some examples, the plurality ofpower stages may be located on the same printed circuit board (PCB)(e.g., which may be located inside the single shared housing orenclosure of the power device 106). Providing a plurality of powerstages in the same housing and/or on the same circuit board may have theadvantage of reducing the number of components and/or electricalconnectors otherwise needed in the power system (e.g., MC4 connectorswhich generally are needed to connect between devices in differenthousings or enclosures, and/or other connectors, such as circuit boardjumpers, that might be used to connect between a plurality of differentPCBs that may be located in a single housing or enclosure). Reducing thenumber of components and/or electrical connectors otherwise needed inthe power system may potentially reduce the complexity and/or cost ofcomponents (e.g., related to the need for having more components) usedin a system and/or reduce electrical losses in the power system. Fewerconnections (e.g., MC4 connectors) may also provide fewer imperfectconnections during installation. Fewer connections (e.g., MC4connectors) may also provide fewer corroded connections over time ofuse. Imperfect connections and corroded connections may potentially leadto disastrous situations (e.g., arcs and/or fires).

Power system 100 a may include a plurality of controllers (e.g.,controllers Con, Con1, Con2, 116, described herein below), and one ormore of those controllers may be designated as a mastercontroller/central controller 116. In some cases, the central controller116 may be the master controller. In some examples, each power device106 may have its own controller with or without an external centralcontroller 116, and one or more of those internal controllers may bedesignated as a master controller. FIG. 1A shows controller 116 as acentral controller external to power device(s) 106 and system powerdevice(s) 110. In some cases, one or more controllers may be included inpower device(s) 106, system power device(s) 110, and one or more of theinternal controllers may be designated as a central controller/mastercontroller. As an example, the functionality of central controller 116may be included in one or more controllers included as part of powerdevice(s) 106 and system power device(s) 110. For example, powerdevice(s) 106 may have a plurality of controllers, and one or more ofthose controllers may be designated as a master controller whichprovides instructions/indications/signals to one or more othercontrollers.

The one or more controllers of power system 100 a may be configured toreceive and/or transmit instructions assignals/instructions/indications/commands to and/or from one or moreother elements of the power system. As mentioned above, one or morecontrollers may include one or more processors/processing circuits andmemory configured to access data and makedeterminations/calculations/computations.

For simplicity, some connections between controllers and the otherelements of power system 100 a (e.g., power devices 106, system powerdevices 110, switches Q, one or more sensors [e.g., voltage sensorsVsensor, current sensors Isensor, etc., described herein below], etc.)are not shown in FIG. 1A. It will be appreciated that in some examplespower device(s) 106, system power device(s) 110, and/or one or moresensor(s), may be communicatively and/or operably connected to one ormore controller. For example, one or more sensor(s) may provide data tothe one or more controllers.

The one or more sensor(s) may be configured to obtain one or moreparameter/parameter data related to power system 100 a. This one or moreparameter may be an electrical parameter, for example: current, voltage,power, temperature, irradiance, etc.

Providing a plurality of power stages in the same power device 106 mayallow the power device 106 to require fewer elements than if theplurality of power stages were in separate power devices 106.

For example, a power device with a plurality of power stages may have asingle shared controller (e.g., an internal controller, for example,controller Con in FIG. 6A and FIG. 6B), instead of a plurality ofcontrollers. The single controller may be configured to control theplurality of power stages in the power device. As an example, the singlecontroller may be configured to increase power for the plurality ofpower stages in the power device (e.g., by using multiple power pointtracking [MPPT] operations, and/or, for example, the single controllermay be configured to cancel output ripples by controlling the pulsewidth modulation [PWM] of the plurality of power stages so that there isabout a 180 degree phase difference, or another phase difference,between current and/or voltage ripple at the outputs of the differentpower stages. For example, one or more power stages may be configured toproduce output voltage and/or current having a first ripple, and one ormore other power stages may be configured to produce output voltageand/or current having a second ripple such that peaks of the firstripple correspond to troughs of the second ripple, and the total currentand/or voltage may thereby have a lower ripple amplitude, potentiallyincreasing efficiency and power output by the power device. As anotherexample, the single controller may be configured to control separatesignals to each of the plurality of power stages in the power device(e.g., signals to the gates [g] of one or more switches Q).

The shared controller (and/or other circuits/circuitries configured toincrease power) may be configured to take into account different dutycycles used for different power stages of the plurality of power stages.For example, if a first converter is operating at a duty cycle of fiftypercent, and a second converter is also operating at a duty cycle offifty percent, a common controller used to control the first and secondconverter may operate the converter switches at a phase shift of about180 degrees. For example, if a first converter is operating at a dutycycle of fifty percent, and a second converter is operating at a dutycycle of forty percent, a common controller used to control the firstand second converter may operate the converter switches at a phase shiftof slightly more or less than 180 degrees, which may cause an alignmentor near-alignment of a peak voltage/current ripple in the firstconverter with a trough voltage/current ripple in the second converter.

As another example, a power device having a plurality of power stagesmay have a single shared data storage device/memory (not shown) (e.g.,flash memory), instead of a plurality of data storage devices/memories.

As another example, a power device having a plurality of power stagesmay have a single shared software program (not shown), instead of aplurality of software programs (e.g., as may be required if theplurality of power stages were in separate power devices). For example,the single shared software program may be run by a single sharedcontroller or by a plurality of controllers.

As another example, a power device having a plurality of power stagesmay have a single shared power-line communication (PLC)circuit/circuitry (not shown), instead of a plurality of PLCcircuits/circuitries. The single PLC circuit/circuitry may be configuredto control communication (e.g., reception and transmission of signals)to/from each of the power stages separately and/or together. Forexample, the single PLC circuit/circuitry may be configured to transmitdata related to each power stage (e.g., obtained parameter data,measurements, telemetries, etc.) and/or data related to other elementsof the power system (e.g., one or more power sources) separately over apower line connected at an output of one or more of the plurality ofpower stages (e.g., using one or more transmitters [not shown]). Thesingle PLC circuit/circuitry may receive, such as by monitoring a powerline connected at an output of one or more of the plurality of powerstages, data related to the plurality of power stages and/or datarelated to other elements of the power system (e.g., one or more powersources) together and/or separately (e.g., using one or more receivers[not shown]). The single shared PLC circuit/circuitry may be configuredto transmit one or more signals without the use of a signal combiner by,for example, synchronizing transmissions related to separate convertersto be transmitted at different times, and/or by transmitting messagesthat include data related to more than one of the power stages.

As another example, a power device with a plurality of power stages mayhave a single shared discharge/rapid shut down (RSD) circuit/circuitry(e.g., discharge circuitry Dis, described herein below), instead of aplurality of discharge/RSD circuits/circuitries. The single shareddischarge/rapid shut down (RSD) circuit/circuitry may be configured toperform discharge at an input and/or output of one or more power stagesand/or power source(s) (e.g., discharge a voltage related to the powerdevice, for example, discharge an input voltage and/or an output voltagerelated to the power device). In some cases, the shared dischargecircuit may discharge a common input/output shared by one or more powerstages. In some cases, the shared discharge circuit may discharge acommon input/output shared by one or more power stages while one or moreother power stages and/or power source(s) continue to operate withoutperforming discharge.

As another example, a power device with a plurality of power stages mayhave a single shared protection circuit/circuitry (not shown) (e.g.,overvoltage protection, duty cycle disorder protection, leakageprotection, etc.) configured to protect one or more elements of thepower system, instead of a plurality of protection circuits/circuitries.The protection circuit may be configured to provide protection againstsurges at the output of the power device, or may be configured toprovide protection against static overvoltage (e.g., output tolerancesaccording to one or more thresholds). For example, the protectioncircuit may include one or more transient voltage suppressor (TVS) ormetal-oxide varistor (MOV) configured to protect against surges (e.g.,relatively great overvoltage values, for example, hundreds of volts overa maximum voltage threshold). As another example, the protection circuitmay include one or more leakage balancer(s) or Zener diode(s) configuredto perform impedance matching and protect against static overvoltage(e.g., relatively lesser overvoltage values, for example, about 5 voltsover a maximum voltage threshold).

As another example, a power device having a plurality of power stagesmay have a single shared auxiliary power circuit (e.g., auxiliary powerunit Aux in FIG. 5 ), instead of a plurality of auxiliary powercircuits. The single auxiliary power circuit/unit may be configured toprovide power to one or more elements of the power system (e.g.,controllers, switch gate drivers, and/or one or more data storagedevices).

As another example, a power device having a plurality of power stagesmay have one or more shared sensors (e.g., current sensor, voltagesensor, power sensor, temperature sensor, irradiance sensor, etc.),instead of a plurality of sensors (e.g., as may be required if theplurality of power stages were in separate power devices). The one ormore shared sensors may be configured to sense/obtain data related to aplurality of power stages. For example, if the outputs of a plurality ofpower stages are connected in parallel, then a single shared voltagesensor may be configured to measure an output voltage related to theplurality of power stages (e.g., instead of requiring a plurality ofvoltage sensors). As another example, if the outputs of a plurality ofpower stages are connected in series, then a single shared currentsensor may be configured to measure an output current related to theplurality of power stages (e.g., instead of requiring a plurality ofcurrent sensors). In some examples, the plurality of power stages mayshare a single inductor, and a single shared current sensor may beconfigured to measure the inductor current.

As another example, a power device having a plurality of power stagesmay have one or more shared bypass diode, instead of a plurality ofbypass diodes (e.g., as may be required if the plurality of power stageswere in separate power devices). The single bypass diode may beconfigured to bypass a plurality of power stages (e.g. based on/inresponse to one or more bypass indications/bypass conditions, forexample, related to malfunction and/or underproduction of one or moreelement of the power system, for example, one or more of the powerstages). Having a single bypass diode instead of a plurality of bypassdiodes may reduce the losses in the power system when current is flowingthrough the single bypass diode (e.g., as opposed to if the current wasrequired to flow through a plurality of bypass diodes instead, with eachbypass diode incurring losses).

As another example, a power device having a plurality of power stagesmay have a single shared capacitor (e.g., output capacitor and/or inputcapacitor), instead of a plurality of capacitors (e.g., outputcapacitors and/or input capacitors, for example, as may be required ifthe plurality of power stages were in separate power devices). Thesingle capacitor (e.g., output capacitor and/or input capacitor) may beconfigured to store energy for a plurality of power stages.

As another example, a power device having a plurality of power stagesmay have a single shared inductor (e.g. an output inductor) and/or asingle shared inductor core with separate windings, instead of aplurality of inductors (e.g., as may be required if the plurality ofpower stages were in separate power devices). The single shared inductorand/or the single shared inductor core with separate windings may besmaller and/or may take up less space (e.g., on a printed circuitboard), compared to a plurality of inductors.

In some cases, providing a plurality of power stages in the same powerdevice 106 while not reducing a number of certain elements (e.g., thenumber of elements required if the plurality of power stages were inseparate power devices 106) may allow the power device 106 to beconfigured with additional functionalities (e.g., that might not beotherwise possible, for example, if the power device 106 had only asingle element instead of a plurality of elements).

For example, if a power device only has a single auxiliary powercircuit/unit and a single controller then the controller might not beable to obtain data related to a solar panel connected at the input tothe power device at relatively lesser voltage values (e.g., less than athreshold, such as an auxiliary threshold voltage of the controller; forexample, less than about 12 V, less than about 5 V, at about 0 V, and/orat less than about 0 V), since a certain threshold voltage output by thesolar panel may be required for the auxiliary power circuit/unit topower itself. However, in a case where the power device has a pluralityof auxiliary power circuits/units connected to a corresponding pluralityof power sources (e.g., solar panels) then one or more first auxiliarypower circuit/unit may be used to provide auxiliary power to theplurality of power stages of the power device, while another auxiliarypower circuit/unit may be used to help one or more element of the powersystem (e.g., one or more controller) to obtain data related to thepower system (e.g., a solar panel connected to the power device) even atrelatively lesser voltage values. For example, data obtained at arelatively lesser voltage may be used to produce one or more tools(e.g., graphs, for example, one or more current-voltage [I-V] curves)that may be used to determine diagnostics related to one or moreelements of the power system. The obtained parameter data may be used tohelp determine a faulty and/or malfunctioning element of the powersystem (e.g., one or more switches/diodes, for example, a burnt diode,or a solar panel suffering from potential induced degradation). Asanother example, one or more auxiliary power circuits/units may be usedto provide auxiliary power functions for the plurality of power stagesof the power device, while one or more other auxiliary powercircuits/units may be used to help one or more element of the powersystem (e.g., one or more controller) to perform a current-voltageoperating point search (e.g., a sweep of the whole I-V curve, forexample, not necessarily by the peak power point) and/or a peaksweep/peak search (e.g., to determine an operating voltage value thatmay provide a maximum power output of one or more power sources). Forexample, the current-voltage operating point search and/or peaksweep/peak search may even include parameter data obtained at relativelylesser voltage values. The current-voltage operating point search and/orpeak sweep/peak search may be done to determine an operating point.

As another example, the power device having a plurality of auxiliarypower circuits/units may allow the power device to begin operation evenwhen only one of the power sources is producing power at a sufficientthreshold (e.g., without requiring additional power sources to beproducing power at a sufficient threshold). As an example, the pluralityof auxiliary power circuits/units may be connected to the differentrespective power source(s) and/or one or more controller via ashared/common ground potential (described in greater detail below). Forexample, if a first power source/plurality of power sources is producingpower above a certain threshold (e.g., the PV module is receiving acertain amount of irradiance), then at least one of the plurality ofauxiliary power sources may receive sufficient voltage (e.g., a wake-upsignal) to begin operation. In this case, power may be provided to oneor more controllers which may be configured obtain parameter datarelated to/monitor the power system. This may allow one or more elementsof the power system (e.g., one or more power sources, one or more powerdevices, one or more controllers, etc.) to be monitored and/or beginproduction/begin operation at an early point in the day then might bepossible if the power device only had a single auxiliary powercircuit/unit. This may also allow one or more elements of the powersystem (e.g., one or more power sources, one or more power devices, oneor more controllers, etc.) to be monitored and/or begin production/beginoperation even when that element is not producing sufficient voltage forother reasons (e.g., shading or malfunction).

As another example, the power device having a plurality of power stagesmay have a plurality of PLC circuits/circuitries. The plurality of PLCcircuits/circuitries and/or one or more controllers controlling the PLCcircuits may be configured to be synchronized to avoid issues of theplurality of PLC circuits/circuitries performing certain operations atthe same time. For example, the plurality of PLC circuits/circuitriesmay be configured so that each PLC circuit/circuitry transmits signalsin turn (e.g., one at a time, so that a plurality of PLCcircuits/circuitries are not transmitting together at about the sametime, for example to avoid any collisions/interferences between thetransmission signals). It will be appreciated that the plurality of PLCcircuits/circuitries and/or one or more controllers controlling the PLCcircuits may be configured to communicate with one another (e.g.coordinate operation with one another, for example, to help ensure thatthe operation of one PLC circuit/circuitry is not interfering with theoperation of another PLC circuit/circuitry). It will also be appreciatedthat in a power device with a plurality of power stages having aplurality of PLC circuits/circuitries, the communication between theplurality of PLC circuits/circuitries and/or other elements of the powersystem (e.g., one or more controllers) may be relatively quick (e.g.,due to the PLC circuits/circuitries and/or other elements being locatedrelatively close to one another, for example, in the same enclosure orhousing, and/or on the same circuit board, such that the signals mayonly have to travel a relatively short distance). Communication betweenthe plurality of PLC circuits/circuitries may also be used tosynchronize one or more operations of the plurality of power stages.

As another example, the power device having a plurality of power stagesmay have a plurality of controllers (e.g., low voltage [LV] controllers,for example controllers Con1, Con2 shown in some of the figures) thatmay be configured to control one or more elements of the power system.The plurality of controllers may be configured to increase power for theplurality of power stages in the power device (e.g., using multiplepower point tracking [MPPT] operations). As an example, the plurality ofcontrollers (and/or other circuits/circuitries configured to increasepower) may be synchronized (e.g., may share a communication bus and/orother method of sharing synchronization information) and may beconfigured to operate to generate one or more information signals and/orpower signals (e.g., in order to reduce and/or cancel out ripples, forexample, at an output of the power device). As an example, the pluralityof controllers (and/or other circuits/circuitries configured to increasepower) may be configured to perform interleaving while taking intoaccount phase differences. The plurality of controllers (and/or othercircuits/circuitries configured to increase power) may be configured tobe synchronized and/or to synchronize one or more operations of theplurality of power stages (e.g., the plurality of controllers and/orother circuits/circuitries configured to increase power may beconfigured to cancel output ripples by controlling the pulse widthmodulation [PWM] of the plurality of power stages so that there is abouta 180 degree phase difference, or another phase difference, between theoutputs of the different power stages).

For example, the plurality of controllers may be configured to share thesame earth/ground potential and/or communicate with one another andshare data. The shared earth/ground potential may provide a path for thecurrent to return to the respective power source/power stage. The sharedearth/ground potential may also provide a similar reference voltage fora plurality of elements of the power system/power device which mayfacilitate communication between the plurality elements (e.g., fewersteps and/or other elements may be needed to allow communication than ifthe plurality of elements had different voltages for their referencevoltages instead of the same shared earth/ground potential). A furtherexample will be given below with reference to FIG. 3D.

As another example, the power device having a plurality of power stagesmay have a plurality of controllers and only a single shared auxiliarypower circuit/unit. In this example also, data may be able to beobtained at relatively lesser voltage values (e.g., less than athreshold, for example, less than about 12 V, less than about 5 V, atabout 0 V, and/or less than about 0 V), since one or more controller ofthe plurality of controllers may be configured to ensure that auxiliarypower functions for the plurality of power stages of the power deviceare provided (e.g., by the single auxiliary power circuit/unit) whileone or more other controller of the plurality of controllers may beconfigured to obtain data related to the power system even at relativelylesser voltage values (e.g., since the other one or more controller isconfigured to ensure that at any given time only one of the respectivepower source[s] is controlled to be less than an auxiliary threshold,for example, less than about 12 V, or less than about 5 V, etc.). As anexample, data obtained at a relatively lesser voltage may be used toproduce one or more tools (e.g., graphs, for example, one or morecurrent-voltage [I-V] curves) that may be used to determine diagnosticsrelated to one or more elements of the power system. The obtainedparameter may be used to help determine a faulty and/or malfunctioningelement of the power system (e.g., one or more switches/diodes, forexample, a burnt diode). As another example, one or more one or morecontroller of the plurality of controllers may be used to provideauxiliary power functions for the plurality of power stages of the powerdevice, while the single auxiliary power circuit/unit may be used tohelp one or more element of the power system (e.g., one or morecontroller) to perform a current-voltage operating point search and/orpeak sweep/peak search (e.g., to determine an operating voltage valuethat may provide a maximum power output of one or more power sources).For example, the current-voltage operating point search and/or peaksweep/peak search may even include parameter data obtained at relativelylesser voltage values. For example, a slope of an I-V curve at lowvoltage values may provide indications of potential-induced degradation(PID). A controller receiving power from an auxiliary power converterconnected to a single solar panel cannot obtain I-V operating pointvalues for the single solar panel at a voltage below a certainthreshold, for example, about 12 V or about 5 V, since the auxiliaryconverter might not be able to provide the controller with sufficientoperational power when the solar panel outputs below the threshold(e.g., about 12 V or about 5 V).

As another example, a power device with a plurality of power stages mayhave a plurality of discharge/rapid shut down (RSD) circuits/circuitries(e.g., discharge circuits Dis1, Dis2, described herein below). One ormore of the discharge/rapid shut down (RSD) circuits/circuitries may beconfigured to perform discharge at an input and/or output of one or morepower stages and/or power source(s) while one or more other power stagesand/or power source(s) continue to operate without discharge (e.g., oneor more of the discharge/RSD circuits/circuitries do not performdischarge).

Providing a plurality of power stages in the same power device 106 whileincreasing the elements (e.g., the number of elements required even ifthe plurality of power stages were in separate power devices 106) mayallow the power device 106 to be configured with additionalfunctionalities. For example, a power device with a plurality of powerstages may have additional bypass circuits/bypass diodes (e.g., morethan may be provided if the plurality of power stages were in separatepower devices 106). As an example, a plurality of bypass circuits/bypassdiodes may be configured to bypass a single power stage, and one or moreadditional bypass circuits/bypass diodes may be configured to bypass aplurality of power stages. In some cases, this may advantageously enablebypassing of a single one of the converter(s)/power stage(s) where onlya single power stage is underperforming and/or malfunctioning, and mayenable bypassing of several converter(s)/power stage(s) where severalconverter(s)/power stage(s) are underperforming or malfunctioning whileincurring losses associated with a single bypass device.

FIG. 1B shows a power system 100 b according to examples of the presentsubject matter. Power system 100 b may include a plurality of powerdevices 106 configured to be connected to at least one system powerdevice 110.

Power system 100 b shows may be similar to other power systems 100 shownherein, except that power system 100 b shows that string 114 may includea plurality of power sources 102C, 104C that may be connected in seriesto a power device 106C.

FIG. 2A shows a power system 100 c according to examples of the presentsubject matter. Power system 100 c may be similar to other power systems100 shown herein, except that power system 100 c shows that a powersystem 100 may include a plurality of series strings 114A, . . . , 114Nof power devices connected in parallel via the bus 108 (e.g., a DC bus).The plurality of series strings 114A, . . . , 114N may be connected toone or more system power device 110 via the bus 108. Each series string114A, . . . , 114N, may include one or more power devices 106A, . . . ,106N, 126A, . . . , 126N that have a plurality of power sources 102A, .. . , 104A, 102N, . . . , 104N, 122A, . . . , 124A, 122N, . . . , 124N,connected to them. Power sources 122, 124 may be similar to other powersources 102 shown herein. Power devices 126 may be similar to otherpower devices 106 shown herein.

FIG. 2B shows a power system 100 d according to examples of the presentsubject matter. Power system 100 d may include a plurality of seriesstrings 114Ad, . . . , 114Nd of power devices connected in parallel viathe bus 108 (e.g., a DC bus). The plurality of series strings 114Ad, . .. , 114Nd may be connected to one or more system power device 110 viathe bus 108. Power system 100 d may be similar to other power systems100 shown herein, except that power system 100 d shows that each seriesstring 114Ad, . . . , 114Nd, may include one or more power devices 106A,126A connected to a plurality of power sources 102A, 104A, 122A, 124A,and one or more power devices 106Nd, 126Nd connected to a single powersource 102Nd, 122Nd. Although the one or more power devices 106Nd, 126Ndare shown connected to a single power source 102Nd, 122Nd, these powerdevices 106Nd, 126Nd may each have a plurality of power stages as shownin various other power devices shown herein. These power devices 106Nd,126Nd while shown connected to a single power source 102Nd, 122Nd may beconfigured to be connected to a plurality of power sources similar toother power devices shown herein. For example, these power devices106Nd, 126Nd may include a plurality of inputs that are not shown in usein FIG. 2B.

FIG. 3A to FIG. 6B show examples of various power devices 106 accordingto examples of the present subject matter. The power devices 106 shownin FIG. 3A to FIG. 6B may be part of the various power systems 100 shownin FIG. 1A to FIG. 2B. FIG. 3A to FIG. 3H show examples of power devices106 with series-connected power stages 201, 202 according to examples ofthe present subject matter.

FIG. 3A shows a power device 106 a according to examples of the presentsubject matter. Power device 106 a includes a plurality of power stages201 a, 202 a. Each power stage 201 a, 202 a is configured to beconnected to at least one respective power source. The respective powersource may be a single power source or a plurality of power sources(e.g., connected in series and/or parallel, for example, as shown inFIGS. 7-10 ). For example, a first power source may be connected toinput terminals W1, X1, of a first power stage 201 a, and a second powersource may be connected to input terminals W2, X2, of a second powerstage 202 a.

As mentioned above, power stage 201 a, 202 a may be, for example, one ormore: DC to DC converter(s) (e.g., buck converters, boost converters,buck/boost converters, buck+boost converters, Cuk converters, etc.), DCto AC converter(s)/inverter(s), micro-inverter(s), flyback converters,etc.

In the example of FIG. 3A, power stages 201 a, 202 a are shown as DC toDC buck converters (in a buck configuration) that are be configured toreceive power on a first plurality of terminals. The first plurality ofterminals may be a pair of terminals, including a first input terminalW1, W2 and a second input terminal X1, X2, which may receive arespective input voltage Vi1, Vi2 from respective power sources (e.g.,one or more PV modules). The buck converter (also known as a step-downconverter) is a DC to DC power converter that steps down the respectivefirst input voltage Vi1, Vi2 across the first pair of terminals W1, W2and X1, X2 to a respective reduced second output voltage Vo1, Vo2 acrossa second plurality of terminals which may be a pair of terminals,including a first output terminal Y1, Y2 and a second output terminalZ1, Z2. The buck converter may convert current flowing between therespective first pair of terminals W1, W2 and X1, X2 to an increasedcurrent flowing between the respective second pair of terminals Y1, Y2and Z1, Z2.

The respective first input terminal W1, W2 may be connected to the drain(d) of a respective first switch Q1, Q2. The respective first inputterminal W1, W2 may also be connected to a first terminal of respectiveinput capacitors C1, C2, and a first terminal of respective auxiliarypower units Aux1, Aux2.

The respective second input terminal X1, X2 may be connected to a secondterminal of respective input capacitors C1, C2, a second terminal ofrespective auxiliary power units Aux1, Aux2, the source (s) of arespective second switch Q11, Q22, a first terminal of a respectivediode D1, D2, a first terminal of respective output capacitors C11, C22,and to respective first output terminals Z1, Z2. Diode D1, D2 may be abypass diode, and the first terminal of diode D1, D2 may be an anode ofthe diode D1, D2. The respective second input terminal X1, X2 may alsobe connected to a terminal of respective controllers, Con1, Con2 (e.g.,low voltage [LV] controllers) (similar to the connection of terminalsX1, X2 to respective controllers Con1, Con2, shown in FIG. 4C).

Auxiliary power units Aux1, Aux2 may be connected to the respectivecontrollers, Con1, Con2 (e.g., using any appropriate connection, forexample, electrical, physical, communication, etc.).

Controllers Con1, Con2 may be connected to the gates (g) of therespective switches Q1, Q11, Q2, Q22 (e.g., using any appropriateconnection, for example, electrical, physical, communication, etc.).

Auxiliary power may be used to power a controller configured to activateone or more switches (e.g., Q1, Q11, Q2, Q22), for example, in a casewhere one or more power source is underproducing/malfunctioned.Auxiliary power may be provided by voltage Vi1, voltage Vi2, and/or anexternal power source, external to the power device 106 a. For example,the external power source may be power from a utility grid, a storagedevice, a different power source, etc.

The drain (d) of the respective second switch Q11, Q22 may be connectedto the source (s) of the respective first switch Q1, Q2, and to a firstterminal of a respective inductor L1, L2.

A second terminal of the respective inductor L1, L2 may be connected toa second terminal of respective diode D1, D2, a second terminal ofrespective output capacitor C11, C22, and respective second outputterminals Y1, Y2. The second terminal of the respective diode D1, D2,may be the cathode of the respective diode D1, D2.

Switches Q1, Q11, Q2, Q22 may be, for example, one or more: field effecttransistor (FET), metal-oxide-semiconductor field-effect transistor(MOSFET), bipolar junction transistor (BJT), insulated-gate bipolartransistor (IGBT), Silicon Carbide (SiC) switch, Gallium Nitride (GaN)switch, etc. Switches Q1, Q11, Q2, Q22 are shown in FIG. 3A as MOSFETs.Switches Q1, Q11, Q2, Q22 may be active switches (e.g., MOSFETs whereswitch Q11, Q22 is controlled to be ON when switch Q1, Q2 is OFF, andvice versa), relays, and/or the like. In some implementations, switchesQ11, Q22 may be replaced with a diode corresponding to the parasiticdiode shown as part of switches Q11, Q22.

Power stages 201 a, 202 a may be connected in a series connection (e.g.,having outputs connected via connection 250, for example, second outputterminal Z1 of the first power stage 201 a may be connected to firstoutput terminal Y2 of the second power stage 202 a). The total outputvoltage Vout of power device 106 a may be the combination of the outputvoltage Vo1 of the first power stage 201 a and the output voltage Vo2 ofthe second power stage 202 a (e.g., the total output voltage Vout may beabout equal to output voltage Vo1 added together with output voltageVo2).

The output current (Iout) of power device 106 a may be the shared outputcurrent (Iout) of the first power stage 201 b and the second power stage202 b (e.g., Iout may be about equal to the current of the firstinductor L1 [IL1] which may be about equal to the current of the secondinductor L2 [IL2]).

Power device 106 a may be configured to control the output of powerdevice 106 a (e.g., one or more output voltage Vo1, Vo2, Vout).

Alternatively (or additionally, in case of a buck+boost converter), aboost converter (e.g., power stage 202 ad in FIG. 3D) may be used forone or more of the power stages 201 a, 202 a. A boost converter (alsoknown as a step-up converter) is a DC to DC power converter which stepsup a respective first voltage Vi1, Vi2 at the first pair of inputterminals W1, W2 and X1, X2 to a second voltage Vo1, Vo2 at the secondpair of output terminals Y1, Y2 and Z1, Z2. The boost converter mayaccordingly convert the current flowing between the first pair of inputterminals W1, W2 and X1, X2 to a reduced current between the second pairof output terminals Y1, Y2 and Z1, Z2.

Although only two power stages 201 a, 202 a are shown in FIG. 3A andother figures, this is for the sake of simplicity, and it is to beunderstood that the power devices 106 may include a greater number ofpower stages (e.g., more than two power stages, for example, connectedusing parallel and/or series connections).

FIG. 3B shows a power device 106 ab according to examples of the presentsubject matter. Power device 106 ab may include a plurality of powerstages 201 ab, 202 ab connected in series at the output of power device106 ab. Power device 106 ab may be similar to other power devices shownherein except that power device 106 ab shows that the power device 106may include an additional bypass diode D12. The additional bypass diodeD12 is shown connected across the output of power device 106 ab. Bypassdiode D12 may be configured to bypass the plurality of power stages 201ab, 202 ab (e.g., in response to one or more bypass conditions, forexample, if a power source and/or a power device is malfunctioning orunderproducing). One possible advantage of having an additional bypassdiode D12 is that in a situation where both power stages 201 ab, 202 abare bypassed, then in a situation where there are only respective bypassdiodes D1, D2 (e.g., as shown in FIG. 3A) then there may be losses(e.g., power losses) according to both of the diodes D1, D2. However ina case where there is also an additional bypass diode D12 (which may bea similar diode as each of the diodes D1, D2, e.g., as shown in FIG. 3B)then if both power stages 201 ab, 202 ab are bypassed by the additionaldiode D12 then the power losses may be less than if both alternativebypass diodes D1, D2 were active (e.g., the losses may even be half asmuch if all of the diodes D1, D2, D12 are similar diodes). In addition,power device 106 ab may be configured so that in a situation where bothpower stages 201 ab, 202 ab are to be bypassed, then the additionaldiode D12 may be configured to perform the bypass instead of both of therespective diodes D1, D2 together.

FIG. 3C shows a power device 106 ac according to examples of the presentsubject matter. Power device 106 ac may include a plurality of powerstages 201 ac, 202 ac connected in series at the output of power device106 ac. Power device 106 ac may be similar to other power devices 106shown herein except that power device 106 ac shows that the power device106 may include a shared bypass diode D12. The shared bypass diode D12is shown connected across the output of power device 106 a. Bypass diodeD12 may be configured to bypass the plurality of power stages 201 ac,202 ac (e.g., in response to one or more bypass conditions). In somecases, power device 106 ac might not include respective bypass diodesD1, D2 for each of the respective power stages 201 ac, 202 ac.

FIG. 3D shows a power device 106 ad according to examples of the presentsubject matter. Power device 106 ad may include a plurality of powerstages 201 ad, 202 ad connected in series at the output of power device106 ad. Power device 106 ad may be similar to other power devices 106shown herein, except that power device 106 ad shows that the powerdevice 106 may include one or more power stages 201 ad, 202 ad that areboost converters. For example, power device 106 ad may be an invertingbuck boost device having a first power stage 201 ad that is a buckconverter and a second power stage 202 ad that is a boost converter. Inpower device 106 ad, first power stage 201 ad and second power stage 202ad may be connected with a shared earth/ground potential. Sharedearth/ground potential may provide a path for the current to return tothe respective power source/power stage, and may facilitatecommunication between a plurality of elements (e.g., fewer steps and/orother elements may be needed to allow communication than if theplurality of elements had different voltages for their referencevoltages instead of the same shared earth/ground potential). Forexample, in the power devices 106 a/106 ab/106 ac which include aplurality of power stages 201, 202 connected in series at the output ofthe power device 106, the reference voltage of one of the converters 201(e.g., at the auxiliary unit Aux1) may be different than the referencevoltage of another one of the converters 202 (e.g., at the auxiliaryunit Aux2). As an example, if the output voltage of each power stage201, 202 is about 80 V, then the reference voltage of the auxiliary unitAux2 of power stage 202 may be about 0 V, while the reference voltage ofthe auxiliary unit Aux1 of power stage 201 may be about 80 V (e.g.,about the voltage value of the output voltage Vo2 of power stage 202).This may complicate communication between the plurality of power stages201, 202 and may demand additional elements (not shown) in order tofacilitate communication between the plurality of power stages 201, 202.On the other hand, in power device 106 ad which may have a sharedearth/ground potential for the plurality of power stages 201 ad, 202 ad,then the reference voltage of the auxiliary unit Aux2 of power stage 202ad may be about 0 V (or another shared reference voltage, e.g., 10 V),while the reference voltage of the auxiliary unit Aux1 of power stage201 may also be about 0 V (or another shared reference voltage, e.g.about 10 V) which is about the same reference voltage of the otherauxiliary unit Aux2. This may facilitate communication between elementsof the power device 106 ad (e.g., communication between the respectivecontrollers Con1, Con2).

FIG. 3E shows a power device 106 ae according to examples of the presentsubject matter. Power device 106 ae may include a plurality of powerstages 201 ae, 202 ae connected in series at the output of power device106 ae. Similar to power device 106 ad, power device 106 ae may includea first power stage 201 ae and a second power stage 202 ae connected ina configuration with a shared earth/ground potential.

FIG. 3F shows a power device 106 af according to examples of the presentsubject matter. Power device 106 af may include a plurality of powerstages 201 af, 202 af connected in series at the output of power device106 af. Power device 106 af may include a first power stage 201 af andsecond power stage 202 af connected in a mirror configuration. A mirrorconfiguration may help provide a shared earth/ground potential (somepossible benefits of which may be detailed above). Similar to powerdevices 106 a/106 ab/106 ac, power device 106 af may include a pluralityof power stages 201 af, 202 af that are buck converters.

FIG. 3G shows a power device 106 ag according to examples of the presentsubject matter. Power device 106 ag may include a plurality of powerstages 201 ag, 202 ag connected in series at the output of power device106 ag. Power device 106 ag may be similar to other power devices 106shown herein, except that power device 106 ag shows that the powerdevice 106 may include a shared voltage sensor Vsensor. The sharedvoltage sensor may be arranged across the output terminals of the powerdevice 106 ag, and configured to measure the total combined voltageacross the series of power stages 201 ag, 202 ag. If the plurality ofpower stages 201 ag, 202 ag were in separate power devices, then aplurality of voltage sensors may be used instead of the shared voltagesensor Vsensor.

FIG. 3H shows a power device 106 ah according to examples of the presentsubject matter. Power device 106 ah may include a plurality of powerstages 201 ah, 202 ah connected in series at the output of power device106 ah. Power device 106 ah may be similar to other power devices 106shown herein, except that power device 106 ah shows that the powerdevice 106 may include a plurality of discharge circuits Dis1, Dis2.Each discharge circuit may include one or more discharge resistors andone or more discharge switches (e.g., similar to discharge resistor Rand discharge switch Q shown in FIG. 4E). Each discharge circuit Dis1,Dis2 may be arranged across a respective output of one of the powerstages 201 ah, 202 ah, and configured to perform discharge for thatrespective power stage 201 ah, 202 ah (e.g., each discharge circuit mayoperate independently; for example, each discharge circuitry may becontrolled by one or more controllers to perform discharge separatelyfrom one another based on/in response to one or more dischargeconditions [e.g., a voltage value above a certain threshold, disconnectof one or more switches, etc.] related to the respective power sourcethat the power stage is connected to).

FIG. 4A to FIG. 6B show examples of power devices 106 withparallel-connected power stages 201, 202 according to examples of thepresent subject matter.

FIG. 4A shows a power device 106 b according to examples of the presentsubject matter. Power device 106 b may include a plurality of powerstages 201 b, 202 b configured to be connected to at least onerespective power source. The respective power source may be a singlepower source or a plurality of power sources (e.g., connected in seriesand/or parallel, for example, as shown in FIGS. 11-14 ). For example, afirst power source may be connected to input terminals W1, X1, of afirst power stage 201 b, and a second power source may be connected toinput terminals W2, X2, of a second power stage 202 b.

As mentioned above, power stage 201 b, 202 b may be, for example, one ormore: DC to DC converter(s) (e.g., buck converters, boost converters,buck/boost converters, buck+boost converters, Cuk converters, etc.), DCto AC converter(s)/inverter(s), micro-inverter(s), flyback converters,etc.

In the example of FIG. 4A, power stages 201 b, 202 b are shown as DC toDC buck converters (in a buck configuration), as described above indetail with regards to FIG. 3A.

Unlike power stages 201 a, 202 a of power device 106 a, power stages 201b, 202 b may be connected in a parallel connection (e.g., with theoutput of the first power stage 201 b connected in parallel to theoutput of the second power stage 202 b, for example, the outputs may beconnected in parallel through a pair of connections 260). The outputvoltage Vout of power device 106 b may be the shared output voltage Vo12of the first power stage 201 b and the second power stage 202 b (e.g.,the output voltage Vout may be about equal to the output voltage of thefirst power stage 201 b which may be about equal to the output voltageof the second power stage 202 b). This relatively lesser output voltageof the parallel connection (compared to the series connection) may allowthe power device 106 b to be configured to be connected to more powersources (e.g., PV modules, strings of PV modules, etc., for example,more than in the case of the series connection which may have a greatertotal output voltage for the same number of power sources). The sharedoutput voltage Vo12 may be a voltage across terminals Y12, Z12. A diodeD12 and/or capacitor C12 may be connected between terminals Y12, Z12.

The total output current Iout of power device 106 b may be thecombination of the output current Io1 of the first power stage 201 b andthe output current Io2 of the second power stage 202 b (e.g., the totaloutput current Iout may be about equal to output current Io1 addedtogether with output current Io2). The combined output current of theparallel connection (compared to the series connection) may allow thepower device 106 b to be configured to output a relatively greatercurrent (for example, greater than in the case of the series connectionwhich may have a lesser total output current for the same number ofpower sources). For example, in the case where a first output currentIo1 is about 20 A and a second output current Io2 is about 20 A, thenfor the parallel connection the total output current Iout might be about40 A. In the case of the series connection the output current Iout mightbe about equal to the first output current IL1 and about equal to thesecond output current IL2, so the output current Iout might be about 20A. As an example, if an output current Iout of 20 A was desired for theparallel connection, then power device 106 b may include lesserinductors L1, L2 than may be used in the series connection, since eachinductor L1, L2 in this case might only be required to output about halfof the desired current, for example, if the first output current Io1 isabout 10 A and the second output current Io2 is about 10 A, then thetotal output current Iout for the parallel connection might be about 20A (e.g., Iout=Io1+Io2=10 A+10 A=20 A). Using lesser inductors which eachoutput a relatively lesser current than the series connection may reducelosses (e.g., power losses, for example, less losses than in the case ofthe series connection). A power device with a plurality of power stages201 b, 202 b having their outputs connected in a parallel connection mayhave less losses due to Direct Current Resistance (DCR) (e.g., theresistance of an inductor which may be the result of the resistance ofthe wire used in the winding) than if the outputs were connected in aseries connection. As an example if the DCR for each inductor is about 2mOhm, then the power loss due to DCR may be about 2 mOhm*I{circumflexover ( )}2 (e.g., DCR*I{circumflex over ( )}2). If in the seriesconnection two inductors L1, L2 are required to have a current I ofabout 20 A, whereas in the parallel connection two inductors L1, L2 eachhaving a current I of about 10 A are required, then the power loss dueto DCR may be about four times less in the case of the parallelconnection as opposed to the series connection (e.g.,Iparallel{circumflex over ( )}2/Iseries{circumflex over( )}2=10{circumflex over ( )}2/20{circumflex over ( )}2=100/400=1/4).

Power device 106 b may be configured to control the output of powerdevice 106 b (e.g., one or more output current Io1, Io2, Iout) using oneor more controller.

One or more of the power stages may be configured to compensate for oneor more of the other power stages. For example, if one or more of thepower stages are connected to one or more power sources that areexperiencing a lesser production (e.g., due to malfunction, shading,etc.) then one or more of the other power stages may be configured tohelp compensate for the underperforming converter(s)/power stage(s). Asan example, the output current of each power stage may be controlled tohelp compensate for the underperforming converter(s)/power stage(s)(e.g., by controlling the first output current and/or the second outputcurrent, and/or by controlling the output voltage Vout of the powerdevice, for example, if system power device 110 is a non-fixed voltageinverter). For example, if a desired output current Iout is about 40 A,and a first power stage is capable of producing only about 200 W, whilea second power stage is capable of producing about 600 W, then thesecond power stage may be configured/controlled to produce an outputcurrent Io2 of about 30 A, while the first power stage may beconfigured/controlled to produce an output current Io1 of about 10 A,thereby providing a total output current Iout of about 40 A (e.g.,Iout=Io1+Io2=10 A+30 A=40 A).

A power device 106 b that may control the total output current Iout maybe configured to control the output current according to requirements ofthe load (e.g., the grid, motor, etc.) and/or the storage device (e.g.,battery) connected to the power device 106 b. For example, the powerdevice may be configured to provide a relatively greater output currentIout when connected to/charging a storage device, and to provide arelatively lesser current when connected to a load requiring arelatively lesser current. A power device 106 b may control the totaloutput current Iout by controlling input voltage at the input of powerdevice 106 b to be a certain value, and upon setting the input voltage,the input current to power device 106 b may be about equal to the totalpower provided to power device 106 b, divided by input voltage (currentI=power P/voltage V), and the input current to power device 106 b maycorrespond to total output current Iout.

FIG. 4B shows a power device 106 bb according to examples of the presentsubject matter. Power device 106 bb may include a plurality of powerstages 201 bb, 202 bb connected in parallel at the output of powerdevice 106 bb. Power device 106 bb may be similar to other power devices106 shown herein, except that power device 106 bb shows that the powerdevice 106 may include a shared current sensor Isensor. The sharedcurrent sensor may be arranged between a terminal of one or more of theinductors L1, L2 and an output terminal of the power device 106 bb, andmay be configured to measure the total combined current of the powerstages 201 bb, 202 bb. If the plurality of power stages 201 bb, 202 bbwere in separate power devices, then a plurality of current sensors maybe used instead of the shared current sensor Isensor.

FIG. 4C shows a power device 106 bc according to examples of the presentsubject matter. Power device 106 bc may include a plurality of powerstages 201 bc, 202 bc connected in parallel at the output of powerdevice 106 bc. Power device 106 bc may be similar to other power devices106 shown herein, except that power device 106 bc shows that one or morecontrollers Con1, Con2 of the power device 106 may be connected to thesame earth/ground potential, which (e.g., as described above) mayprovide possible benefits to the power device (e.g., to facilitatecommunication and/or provide relatively quick communication between theplurality of controllers). A similar connection between a controller andthe earth/ground potential is also shown in FIG. 6B.

FIG. 4D shows a power device 106 bd according to examples of the presentsubject matter. Power device 106 bd may include a plurality of powerstages 201 bd, 202 bd connected in parallel at the output of powerdevice 106 bb. Power device 106 bd may be similar to other power devices106 shown herein, except that power device 106 bd shows that the powerdevice 106 may include a shared discharge circuit Dis. The shareddischarge circuit Dis may be arranged across the output terminals of thepower device 106 bd, and may be configured to perform discharge for thepower device 106 bd (e.g., for both power stages 201 bd, 202 bdtogether, for example, discharge circuitry Dis may be controlled by oneor more controllers to perform discharge based on/in response to one ormore discharge conditions [e.g., a voltage value above a certainthreshold, disconnect of one or more switches, etc.] related to one ormore power source that the power device is connected to). If theplurality of power stages 201 bd, 202 bd were in separate power devices,then a plurality of discharge circuits may be required instead of theshared discharge circuit Dis.

FIG. 4E shows a power device 106 be according to examples of the presentsubject matter. Power device 106 be may include a plurality of powerstages 201 be, 202 be connected in parallel at the output of powerdevice 106 be. Similar to power device 106 bd, power device 106 be mayinclude a shared discharge circuit Dis. The shared discharge circuit Dismay be arranged across the output terminals of the power device 106 be,and may be configured to perform discharge for the power device 106 be.The shared discharge circuit Dis may include a discharge resistor R anddischarge switch Q. For example, if one or more discharge conditions areobtained by one or more controllers, then those one or more controllersmay active the discharge circuitry (e.g., close the discharge switch Q),which may discharge a voltage by inducing current to flow through thedischarge resistor R.

Similar to what was shown with the shared bypass diode, the powerdevices 106 may have other shared elements (or additional elements) asdescribed above (e.g., the shared elements may include a shared:capacitor, inductor, controller, auxiliary power unit, sensor, PLC, RSD,etc.). As an example, one or more shared sensor (e.g. shared currentsensor) may be connected at an input of the power device and/or powerstages, and the shared sensor may be configured to measure/obtain datarelated to the plurality of power stages (e.g., sense/measure adifferential [input] current between the plurality of power stages).

As also described above, the power device may include a plurality ofrespective elements (e.g., controllers, auxiliary power units, bypassdiodes, etc.) and/or additional elements that may be configured toprovide additional functionalities (e.g., that may be configured to helpobtain data that may be used to build graphs related to theoperation/performance of elements of the power system [e.g., powersources, power devices, switches/diodes, etc.]).

FIG. 5 shows a power device 106 c according to examples of the presentsubject matter. Power device 106 c may include power stages 201 c, 202 cthat are connected in a parallel connection. Power device 106 c may besimilar to other power devices 106 shown herein, except that powerdevice 106 c shows the power stages 201, 202 shown side-by-side in FIG.5 .

Similar to other power devices 106 shown herein (for example, powerdevice 106 b), the power stages 201 c, 202 c of power device 106 c havea shared earth/ground potential. The earth/ground potential may be avirtual/local earth/ground potential (as opposed to being electricallyconnected to the actual earth/ground). For example, the earth/groundpotential may be related to a voltage (e.g., a floating voltage)relative to the actual earth/ground potential.

The shared earth/ground potential may help the power device 106 to haveshared elements (e.g., fewer elements than if the power device did nothave a plurality of power stages). This may have the advantage offacilitating communication between a plurality of controllers (e.g., byproviding them with the same reference voltage, or by using a singlecontroller instead of a plurality of controllers since the singlecontroller may be connected to a plurality of respective auxiliary powerunits and/or respective power source[s] via the shared earth/groundpotential). The shared earth/ground potential may also help the powerdevice 106 to be configured with additional functionalities (e.g., whenthere are elements, such as controllers and/or auxiliary power units,for each of the plurality of power stages). For example, (e.g., to allowthe power device to obtain lesser voltage data and/or perform acurrent-voltage operating point search at relatively lesser voltagesand/or peak sweep/peak search at relatively lesser voltages) since oneelement may be able to perform functions normally performed by anotherelement, this may free up the other element to perform other functionsthat might not be possible in a case where the power device only has asingle element and may not be free to perform such functions or may notbe able to perform functions in certain voltage ranges.

FIG. 6A shows a power device 106 d according to examples of the presentsubject matter. Power device 106 d may include power stages 201 d, 202 dthat are connected in a parallel-output connection. Power device 106 dmay be similar to other power devices 106 shown herein, except thatpower device 106 d shows that the power device 106 may include a singleshared auxiliary power unit Aux and a single shared controller Con(e.g., shared by power stages 201 d, 202 d). The single shared auxiliarypower unit Aux and/or the single shared controller Con may be connectedto each of the plurality of power stages 201 d, 202 d through the sharedearth/ground potential. The single shared auxiliary power unit Auxand/or the single shared controller Con may be connected to each of theplurality of power stages 201 d, 202 d through one or more other sharedterminals. For example, the single shared auxiliary power unit Aux maybe connected to terminal W1, and terminal W1 may be connected toterminal W2 (not shown) thereby providing a shared terminal W12 (notshown). Terminal W1 may be connected to terminal W2 via one or moreelectrical element (e.g., one or more diode [not shown]). The singleshared auxiliary power unit Aux and/or the single shared controller Conmay be configured to operate for the plurality of power stages 201 d,202 d.

FIG. 6B shows a power device 106 db according to examples of the presentsubject matter. Power system device 106 db may include a plurality ofpower stages 201 db, 202 db connected in parallel at the output of powerdevice 106 db. Power device 106 db may also have a single sharedauxiliary power unit Aux and a single shared controller Con (e.g.,shared by power stages 201 db, 202 db). The single shared auxiliarypower unit Aux and/or the single shared controller Con may be connectedto each of the plurality of power stages 201 db, 202 db through theshared earth/ground potential. Power device 106 db may be similar toother power devices 106 shown herein, except that power device 106 dbshows that the single shared auxiliary power unit Aux and/or the singleshared controller Con may also be connected to each of the plurality ofpower stages 201 db, 202 db through one or more electrical elements. Forexample, the single shared auxiliary power unit Aux may be connected topower stage 201 db via a diode D11 connected between terminal W1 and theauxiliary power unit Aux. The single shared auxiliary power unit Aux mayalso be connected to power stage 202 db via a diode D22 connectedbetween terminal W2 and the auxiliary power unit Aux. The single sharedcontroller Con may be connected to the plurality of power stages 201 d,202 d via the single shared auxiliary power unit Aux (e.g., the singleshared controller Con may be directly connected to the single sharedauxiliary power unit Aux). The single shared controller Con may beconnected to the shared earth/ground potential to provide a path for thecurrent to return to the respective power source/power stage. Forexample, if a current/signal is provided by the first power source/powerstage 201 db (e.g., represented by voltage Vpv1) it may flow through thefirst diode D11 to the controller Con (e.g., via auxiliary power unitAux) and a current/signal may return to the first power source/powerstage 201 db via the shared earth/ground potential. If a differentcurrent/signal is provided by the second power source/power stage 202 db(e.g., represented by voltage Vpv2) it may flow through the second diodeD22 to the controller Con (e.g., via auxiliary power unit Aux) and acurrent/signal may return to the second power source/power stage 202 dbvia the shared earth/ground potential.

For example, power may be provided to one or more of the plurality ofpower stages 201, 202 (e.g., one or more of the controllers) from apower source (e.g., one or more of the respective power sourcesconnected to one or more of the respective power stages 201, 202). Thispower may be provided to one or more elements of the power device (e.g.,one or more elements of the respective power stage 201, 202 directlyconnected to that respective power source, and/or one or more elementsof another respective power stage 201, 202 directly connected to anotherrespective power source, for example, to one or more controllers, one ormore auxiliary units, one or more PLC units, etc.).

For example, power may be provided to a first power stage 201 (e.g., toa first controller Con1 or shared controller Con, and/or to a firstauxiliary unit Aux1 or shared auxiliary unit Aux) from a first powersource 102 (or auxiliary power unit). Power may also be provided to asecond power stage 202 (e.g., to a second controller Con2 or the sharedcontroller Con, and/or to a second auxiliary unit Aux2 or the sharedauxiliary unit Aux) from the same first power source 102 (or auxiliarypower unit) (e.g., when the other second power source 104 is notproducing power, or the power from the second power source 104 or otherauxiliary unit is being used for a different function, for example toperform a current-voltage operating point search and/or a peaksweep/peak search).

As an example, a first voltage may be provided to first power stage 201db (e.g., to shared controller Con via shared auxiliary unit Aux) from afirst power source 102, represented as Vi1 in FIG. 6B. This may allowthe shared controller to monitor the first power source 102 and/or asecond power source 104, even though power source 104 is not producingpower (e.g., Vi1 is greater than about 12V and Vi2 is less than about 12V or about 0 V).

As another example, a first voltage may be provided to first power stage201 db (e.g., to shared controller Con via shared auxiliary unit Aux)from a first power source 102, represented as Vi1 in FIG. 6B. A secondvoltage may be provided to second power stage 202 db (e.g., to sharedcontroller Con via shared auxiliary unit Aux) from a second power source104, represented as Vi2 in FIG. 6B (e.g., Vi1 is greater than about 12Vand Vi2 is also greater than about 12 V). This may allow the sharedcontroller to perform a current-voltage operating point search and/or apeak sweep/peak search (e.g., even at relatively lesser voltages) on thefirst power source 102 and/or the second power source 104 (since thecontroller and/or auxiliary is receiving sufficient power from the firstsource, it can utilize excess power or power from a different source inorder to perform the additional functions, e.g., a search even below 12V). For example, the first power source 102 may provide 60 V including12 V to the shared auxiliary unit Aux. Normally (e.g., in a case wherethere is not a plurality of power stages in the power device), sincethat 12 V is being provided to auxiliary unit 12 V, then a search may beperformed at a voltage greater than 12 V. However, in a case where thereis a plurality of power stages 201, 202 in the power device 106, thefirst power source 102 may provide power to the auxiliary unit Aux and asecond power source (e.g., second power source 104 or second auxiliarypower unit Aux2) may provide power to the controller Con to perform asearch even at voltages less than 12 V. A similar case may be true forobtaining data and monitoring one or more power source at voltages evenless than 12 V, where since power may be provided to one or morecontroller/auxiliary unit from a first power source (e.g., the firstpower source 102), and power may also be provided to one or morecontroller from a second power source (e.g., the second power source 104or a different auxiliary power unit), then one or more controller may beable to obtain data related to relatively lesser voltages, e.g., lessthan about 12 V, for one or more of the respective power sources 102,104.

FIG. 7 to FIG. 14 show examples of power devices 106 connected to aplurality of power sources 102, 104 according to examples of the presentsubject matter. The power devices 106 shown in FIG. 7 to FIG. 14 may bepart of the various power systems 100 shown in FIG. 1A to FIG. 2B. FIG.7 to FIG. 10 show examples of power devices 106 with series-connectedpower stages 201, 202 according to examples of the present subjectmatter. For example, the power devices 106 with series-connected powerstages 201, 202 shown in FIG. 7 to FIG. 10 may be any of the variouspower devices 106 with series-connected power stages 201, 202 shown inFIG. 3A to FIG. 3H.

FIG. 7 shows a power device 106 e according to examples of the presentsubject matter. Power device 106 e may include a plurality of powerstages 201, 202 having outputs connected in series through a connection250.

In FIG. 7 , each power stage 201, 202 is shown as having inputsconnected to one respective power source 102, 104. The respective powersources 102, 104 may be connected in parallel to power device 106 e(e.g., to the input of power device 106 e).

As mentioned above, any of the power devices 106 (e.g., power devices106 e-1061 shown in FIGS. 7-14 ) may be connected to one or more otherpower devices 106 (e.g., in parallel and/or series). One or more powerdevices 106/strings 114 of power devices 106 may be connected to one ormore system power devices 110 (e.g., in parallel and/or series).

In some examples, one power stage 201, 202 may be connected to a singlepower source and another power stage 201, 202 may be connected to aplurality of power sources.

In some examples, each power stage 201, 202 may be connected to arespective plurality of power sources (as shown in FIGS. 8-10 , andFIGS. 12-14 ).

FIG. 8 shows a power device 106 f according to examples of the presentsubject matter. Power device 106 f may include a plurality of powerstages 201, 202 having outputs connected in series through a connection250.

In FIG. 8 , each power stage 201, 202 is shown as having inputsconnected to a respective plurality of respective power sources 102,104. The respective plurality of power sources 102, 104 may be connectedin parallel to each other. Each respective plurality of power sources102, 104 may also include a plurality of power sources 102 connected inparallel to a first input of power device 106 f (e.g., to a first powerstage 201), and a plurality of power sources 104 connected in parallelto a second input of power device 106 f (e.g., to a second power stage202).

FIG. 9 shows a power device 106 g according to examples of the presentsubject matter. Power device 106 g may include a plurality of powerstages 201, 202 having outputs connected in series through a connection250.

In FIG. 9 , each power stage 201, 202 is shown as having inputsconnected to a respective plurality of respective power sources 102,104. The respective plurality of power sources 102, 104 may be connectedin parallel to each other. Each respective plurality of power sources102, 104 may also include a plurality of power sources 102 connected inseries to a first input of power device 106 g (e.g., to a first powerstage 201), and a plurality of power sources 104 connected in series toa second input of power device 106 g (e.g., to a second power stage202).

FIG. 10 shows a power device 106 h according to examples of the presentsubject matter. Power device 106 h may include a plurality of powerstages 201, 202 having outputs connected in series through a connection250.

In FIG. 10 , each power stage 201, 202 is shown as having inputsconnected to a respective plurality of respective power sources 102,104. The respective plurality of power sources 102, 104 may be connectedin parallel to each other. Each respective plurality of power sources102, 104 may also include a plurality of power sources 102 connected inseries to a first input of power device 106 h (e.g., to a first powerstage 201), and may include a plurality of power sources 104 connectedin parallel to a second input of power device 106 h (e.g., to a secondpower stage 202).

FIG. 11 to FIG. 14 show examples of power devices 106 withparallel-connected power stages 201, 202 according to examples of thepresent subject matter. For example, the power devices 106 withparallel-connected power stages 201, 202 shown in FIG. 11 to FIG. 14 maybe any of the various power devices 106 with parallel-connected powerstages 201, 202 shown in FIG. 4A to FIG. 6B.

FIG. 11 shows a power device 106 i according to examples of the presentsubject matter. Power device 106 i may include a plurality of powerstages 201, 202 having outputs connected in parallel (e.g., through apair of connections 260).

In FIG. 11 , each power stage 201, 202 is shown as having inputsconnected to one respective power source 102, 104. The respective powersources 102, 104 may be connected in parallel to power device 106 i(e.g., to the input of power device 106 i).

FIG. 12 shows a power device 106 j according to examples of the presentsubject matter. Power device 106 j may include a plurality of powerstages 201, 202 having outputs connected in parallel (e.g., through apair of connections 260).

In FIG. 12 , each power stage 201, 202 is shown as having inputsconnected to a respective plurality of respective power sources 102,104. The respective plurality of power sources 102, 104 may be connectedin parallel to each other. Each respective plurality of power sources102, 104 may also include a plurality of power sources 102 connected inparallel to a first input of power device 106 j (e.g., to a first powerstage 201), and a plurality of power sources 104 connected in parallelto a second input of power device 106 j (e.g., to a second power stage202).

FIG. 13 shows a power device 106 k according to examples of the presentsubject matter. Power device 106 k may include a plurality of powerstages 201, 202 having outputs connected in parallel (e.g., through apair of connections 260).

In FIG. 13 , each power stage 201, 202 is shown as having inputsconnected to a respective plurality of respective power sources 102,104. The respective plurality of power sources 102, 104 may be connectedin parallel to each other. Each respective plurality of power sources102, 104 may also include a plurality of power sources 102 connected inseries to a first input of power device 106 k (e.g., to a first powerstage 201), and a plurality of power sources 104 connected in series toa second input of power device 106 k (e.g., to a second power stage202).

FIG. 14 shows a power device 106 l according to examples of the presentsubject matter. Power device 106 l may include a plurality of powerstages 201, 202 having outputs connected in parallel (e.g., through apair of connections 260).

In FIG. 14 , each power stage 201, 202 is shown as having inputsconnected to a respective plurality of respective power sources 102,104. The respective plurality of power sources 102, 104 may be connectedin parallel to each other. Each respective plurality of power sources102, 104 may also include a plurality of power sources 102 connected inseries to a first input of power device 106 l (e.g., to a first powerstage 201), and a plurality of power sources 104 connected in parallelto a second input of power device 106 l (e.g., to a second power stage202).

FIG. 15 to FIG. 19 show examples of graphs and flow charts. For example,the graphs and flow charts may be related to the various power systems100 and power devices 106 shown in FIG. 1A to FIG. 14 .

FIG. 15A and FIG. 15B illustrate graphs according to examples of thepresent subject matter. As mentioned above, power device 106 may beconfigured to determine a peak operating power using a peak sweep/peaksearch even at relatively lesser voltage values. In the example shown ingraph 1500 of FIG. 15A, if a peak sweep/peak search was performed tofind the highest peak then it might not matter if the sweep wasperformed from below a relatively lesser threshold voltage of aboutvoltage VL (e.g., about 12 V or about 5 V) since the first peak P1 shownin graph 1500 is lesser than the second peak P2 in graph 1500 (i.e.,peak P2 is greater than peak P1). However, in the case shown in graph1502 of FIG. 15B, if the first peak P1 is greater than the second peakP2, and the peak sweep/peak search was performed only at voltagesgreater than the relatively lesser threshold voltage of about voltageVL, then the peak sweep/peak search might only find the lesser secondpeak P2 and not the greater first peak P1. In such a case if the lessersecond peak P2 was selected, then the power device/power system may bemissing out on a potentially greater output power. On the other hand, ifin this example the peak sweep/peak search was performed also atvoltages less than the relatively lesser threshold voltage of aboutvoltage VL, then the peak sweep/peak search might also find the greaterfirst peak P1. In such a case the greater first peak P1 may be selected,and the power device/power system may benefit from a potentially greateroutput power.

Performing a peak sweep/peak search at a relatively lesser voltage mayhelp with degradation detection and analysis (e.g., in examples wherethere is a relatively lesser power source, burnt/damaged switches/diodesin the power source, substring optimization, etc.).

FIG. 16 shows a graph according to examples of the present subjectmatter. Power device 106 may be configured to obtain data related to arelatively lesser voltage. For example, other power devices might not beable to obtain data (e.g., power and/or performance data) related to arelatively lesser voltage (e.g., less than a threshold, for example,less than about 12 V, less than about 5 V, about 0 V, and/or less thanabout 0 V). This data may be used to determine data related to thelongevity of elements of the power system (e.g., power devices, powersources, etc.). Each curve 1602, 1604, 1606, 1608 may relate to adifferent time period (e.g., years, months, days, etc.) for one or moreelements of the power system (e.g. one or more power devices). Forexample, curve 1602 may relate to power produced by a power sourceduring the course of a first year, curve 1604 may relate to powerproduced by a power source during the course of a second year, curve1606 may relate to power produced by a power source during the course ofa third year, curve 1608 may relate to power produced by a power sourceduring the course of a fourth year, etc. In the present subject matter,since data may be obtained even at relatively low voltages (e.g.,between about 0 V-VL, e.g., between about 0 V-about 12 V, or about 0V-about 5 V, or even less than 0 volts), then additional conclusions maybe determined related to that data than would be otherwise possible ifthat data was unavailable. As another example, curve 1602 may relate topower produced by a power source during the course of a first hour ofthe day, curve 1604 may relate to power produced by a power sourceduring the course of a second hour of the day, curve 1606 may relate topower produced by a power source during the course of a third hour ofthe day, curve 1608 may relate to power produced by a power sourceduring the course of a fourth hour of the day, etc. As an additionalexample, curve 1602 may relate to power produced by a first power sourceduring the course of a year, curve 1604 may relate to power produced bya second power source during the course of the year, curve 1606 mayrelate to power produced by a third power source during the course ofthe year, curve 1608 may relate to power produced by a fourth powersource during the course of the year, etc.

FIG. 17 shows a flow chart/process 1700 of a method according toexamples of the present subject matter. The shown example relates to apeak power search, but similar operations may be performed for othercurrent-voltage operating point searches (e.g., using a power devicehaving a plurality of auxiliary power units).

In step 1702 a decision is made whether to perform a peak power search.This step may be performed using one or more controllers of the powersystem. The decision may be made based on one or more parameters/factors(e.g., a time parameter, for example related to a time interval forperforming peak power sweeps/peak power searches, and/or whether or notthe necessary elements of the power system [e.g. one or more controller,auxiliary power unit] are available to perform operations related to thepeak sweep/peak search).

If in step 1702 the decision is not to perform the peak power search,then this step may be performed again at a subsequent time (e.g., aftera certain interval of time, and/or based on/in response to one or moreobtained signals and/or parameters).

If in step 1702 the decision is to perform the peak power search, thenthe process 1700 may proceed to step 1704.

In step 1704 a peak power search is performed. This peak sweep/peaksearch may be performed using one or more controllers of the powersystem. This peak sweep/peak search may be performed at relativelylesser voltage values.

In step 1706 a peak power voltage is determined. This peak power voltagemay be determined using one or more controllers of the power system.This peak power voltage may be determined using data obtained duringstep 1704 (e.g., including data obtained at relatively lesser voltagevalues). This peak power voltage may be determined at least in part bybuilding an I-V curve with obtained data (e.g., a graph similar to graph1500 or graph 1502 of FIGS. 15A and 15B).

In step 1708 one or more element of the power system (e.g., one or morepower device, power stage, etc.) is operated according to the determinedpeak power voltage (e.g., determined in step 1706).

The process 1700 starting at step 1702 may then be repeated again at asubsequent time (e.g., after a certain interval of time, and/or basedon/in response to one or more obtained signals and/or parameters).

FIG. 18 shows a flow chart/process of a method 1800 according toexamples of the present subject matter. The shown example relates to apeak power search, but similar operations may be performed for othercurrent-voltage operating point searches (e.g., using a power devicehaving a plurality of auxiliary power units).

In step 1802 data is obtained related to a relatively lesser voltage.This step may be performed using one or more controllers of the powersystem (e.g., using a power device 106 with a plurality of controllersand/or a plurality of auxiliary power units). This data may be obtainedby performing a peak sweep/peak search at relatively lesser voltagevalues (e.g., similar to the peak sweep/peak search done in step 1704 ofFIG. 17 , for example, including data obtained at relatively lesservoltage values).

In step 1804 a diagnostic may be performed on the obtained data. Thisstep may be performed using one or more controllers of the power system.For example, the diagnostic may include one or more determinationsrelated to the performance and or health of one or more element of thepower system (e.g., one or more power source, one or more power device,power stage, etc.). The diagnostic may cause one or more furtheroperations based on the diagnostic (e.g., the generation of one or moresignal [audio and/or visual] and/or a change in operation of one or moreelements of the power system, for example the bypass or shut down of oneor more elements). As an example, the obtained data may be used to buildone or more graphs (e.g., related to the performance of one or moreelements of the power system; for example, graphs similar to graph 1500,graph 1502, and graph 1600, of FIGS. 15A, 15B, and 16 ).

The process 1800 starting at step 1802 may then be repeated again at asubsequent time (e.g., after a certain interval of time, and/or basedon/in response to one or more obtained signals and/or parameters).

FIG. 19 shows a flow chart/process 1900 of a method according toexamples of the present subject matter.

Process 1900 may be used to help synchronize the transmissions of one ormore controllers and/or PLC units of a power device 106 (e.g., in a casewhere the power device has a plurality of controllers and/or PLC units).

In step 1902 a decision is made whether one or more controller/PLC unitis transmitting. This step may be performed using one or more othercontrollers of the power system. The decision may be made based on oneor more obtained parameters (e.g., a time parameter, electricalparameter, communication parameter, etc.).

If in step 1902 the decision is that one or more controller/PLC unit istransmitting, then this step may be performed again at a subsequent time(e.g., after a certain interval of time, and/or based on/in response toone or more obtained signals and/or parameters).

If in step 1902 the decision is that one or more controller/PLC unit isnot transmitting, then the process 1900 may proceed to step 1904.

In step 1904 a signal is transmitted. This signal may be transmittedusing one or more controllers/PLC units of the power system.

The process 1900 starting at step 1902 may then be repeated again at asubsequent time (e.g., after a certain interval of time, and/or basedon/in response to one or more obtained signals and/or parameters).

Although examples are described above, features and/or steps of thoseexamples may be combined, divided, omitted, rearranged, revised, and/oraugmented in any desired manner. Various alterations, modifications, andimprovements will readily occur to those skilled in the art. Suchalterations, modifications, and improvements are intended to be part ofthis description, though not expressly stated herein, and are intendedto be within the spirit and scope of the disclosure. Accordingly, theforegoing description is by way of example only, and is not limiting.

1. An apparatus comprising: a power device configured to convert a firstinput power from a first photovoltaic (PV) power source and a secondinput power from a second PV power source to a combined output power ata power device output, wherein the power device comprises: a first powerstage, comprising: a first pair of input terminals configured toelectrically connect the first PV power source to the first power stage,a first pair of output terminals, and a first power converterelectrically connected between the first pair of input terminals and thefirst pair of output terminals, a second power stage comprising: asecond pair of input terminals configured to electrically connect thesecond PV power source to the second power stage, a second pair ofoutput terminals, and a second power converter electrically connectedbetween the second pair of input terminals and the second pair of outputterminals; wherein the first pair of output terminals are connected tothe second pair of output terminals thereby connecting the first powerstage and the second power stage in parallel at the power device output;at least one controller; and a plurality of auxiliary power units, theplurality of auxiliary power units comprising a first auxiliary powerunit and a second auxiliary power unit, wherein the at least onecontroller is configured to perform an operating point search includingsubstantially 0 volts using power from the first auxiliary power unit.2. The apparatus of claim 1, wherein at least one power stage of thefirst and second power stages comprises a direct current (DC) to DCpower converter.
 3. The apparatus of claim 1, wherein the first andsecond power stages share a ground potential.
 4. The apparatus of claim1, wherein the at least one controller is configured to control thecombined output power of the apparatus.
 5. The apparatus of claim 1,further comprising an output inductor shared by the first and secondpower stages, wherein the output inductor comprises a first winding anda second winding.
 6. The apparatus of claim 1, wherein the plurality ofauxiliary power units comprise auxiliary power converters.
 7. Theapparatus of claim 1, wherein the at least one controller is configuredto obtain data relating to a voltage that is less than a thresholdvoltage of the at least one controller.
 8. The apparatus of claim 1,wherein the at least one controller is configured to be shared by thefirst and second power stages.
 9. The apparatus of claim 1, wherein theat least one controller is electrically connected to each of the firstand second power stages.
 10. The apparatus of claim 1, furthercomprising at least one circuit shared by the first and second powerstages, wherein the at least one circuit is configured to discharge avoltage relating to the power device.
 11. The apparatus of claim 1,wherein the first and second power stages are located on a singleprinted circuit board (PCB).
 12. The apparatus of claim 1, wherein thepower device output is configured to be connected to a second powerdevice output of a second apparatus of claim
 1. 13. A system comprising:a first photovoltaic (PV) power source and a second PV power source; apower device configured to convert a first input power from the first PVpower source and a second input power from the second PV power source toa combined output power at a power device output, wherein a first powerstage is electrically connected to the first PV power source via a firstpair of input terminals, and wherein the first power stage comprises: afirst pair of output terminals, and a first power converter electricallyconnected between the first pair of input terminals and the first pairof output terminals, and wherein a second power stage is electricallyconnected to the second PV power source via the second pair of inputterminals, and wherein the second power stage comprises: a second pairof output terminals, and a second power converter electrically connectedbetween the second pair of input terminals and the second pair of outputterminals, wherein the first pair of output terminals are connected tothe second pair of output terminals thereby connecting the first powerstage and the second power stage in parallel at the power device output,at least one controller, and a plurality of auxiliary power units, theplurality of auxiliary power units comprising a first auxiliary powerunit and a second auxiliary power unit, wherein the at least onecontroller is configured to perform an operating point search includingsubstantially 0 volts using power from the first auxiliary power unit.14. The system of claim 13, wherein at least one power stage of thefirst and second power stages comprises a direct current (DC) to DCpower converter.
 15. The system of claim 13, wherein the at least onecontroller is configured to control the combined output power of thepower device.
 16. The system of claim 13, further comprising a secondpower device, wherein the power device output is connected to a secondpower device output of the second power device.
 17. A method comprising:converting, by a first power stage of a plurality of power stages, afirst input power received from a first photovoltaic (PV) power sourcevia a first pair of input terminals of the first power stage;converting, by a second power stage of the plurality of power stages, asecond input power received from a second PV power source via a secondpair of input terminals of the second power stage, wherein a first pairof output terminals of the first power stage are connected to a secondpair of output terminals of the second power stage thereby connectingthe first power stage and the second power stage in parallel at a powerdevice output; generating, at the power device output, a combined outputpower by combining the converted first input power and the convertedsecond input power; and performing, by at least one controller poweredby a first auxiliary power unit of a plurality of auxiliary power units,an operating point search including substantially 0 volts.
 18. Themethod of claim 17, wherein the first power stage comprises a firstpower converter and the second power stage comprises a second powerconverter.
 19. The method of claim 17, further comprising controlling,by the at least one controller, the combined output power of a powerdevice.
 20. The method of claim 17, further comprising discharging, byat least one circuit shared by the plurality of power stages, a voltagerelating to a power device.